<div>
    <p style="visibility:hidden">Something_1</p>
    <p hidden>Something_2</p>
    <footer>
        <p style="display:none">Something_3</p>
    </footer>    
</div>
<script>
    function ReturnValue(){
        var countElem = $('div').find('p').length
        -$('div').children('p').length;
        return countElem;
    };    
</script>